99 is at least north-south. Of course, currently it touches *no* other interstates. It ends shy of I-70/I-76 (the highway continues south crossing over 70/76, but there's no direct interchange, a consequence of an earlier decision which was that direct connections between the free Interstate system and toll highways were to be avoided) and currently does not extend north to I-80, though the missing link between end I-99 and the western portion of the bypass around State College (the Mount Nittany Expressway) is at least half under construction now.

I-99 is eventually expected to reach I-86 (former New York 17) at the 86/US15 interchange in Corning. Substantial portions of US-220 and US-15 between I-80 and I-86 are already upgraded, but the I-180 interchange at Williamsport has a substandard ramp which will need to be replaced in what will become northbound I-99.